This invention relates generally to methods and systems for controlling traffic flow and more particularly, to methods and systems for controlling traffic flow using RFID enabled devices.
Traffic flow at street intersections is generally controlled with light signal systems. A light signal system includes a combination of light signal transmitters for various roads approaching the intersection and the required operating devices for controlling the traffic flow. A light signal transmitter may be a transmitting apparatus that transmits visible signals to the traffic participants such as a traffic light. A signal program executes in a local control device for the intersection, in which the signal times for the light signal system are fixed with respect to duration and assignment. At least some known light signal systems are fixed time controlled and others may use traffic-dependent methods for controlling the signal transmitters at an intersection.
The fixed time signal control is a light-signal control with fixed signal times, without an influencing option for the traffic flow. This signal control is based on taking into account the long-term traffic situation at the intersection. The method uses signal programs, operating on the basis of fixed-time tables, with a rigid sequence of automatic operations. Fixed-time controlled methods are relatively inexpensive, but are not flexible over the short run or the long run with respect to changes in the traffic conditions at the intersection.
Traffic-dependent methods take into account short-term traffic situations at the intersection and usually require several detectors, such as induction loops, infrared sensors, or radar detectors for each approach to the intersection. As a result, these control methods are very flexible in the short term, but have only an average flexibility for the long term, so that additional planning becomes necessary. On the whole, these traffic-dependent methods are expensive and require extensive pre-planning to implement.
In addition, the known systems are not able to detect congestion at an intersection and therefore can not reduce congestion of traffic flow through the intersection.